Problem: $-\dfrac{6}{2} - \dfrac{3}{10} = {?}$
Answer: $ = - {\dfrac{6 \times 5}{2 \times 5}} - {\dfrac{3 \times 1}{10 \times 1}} $ $ = - {\dfrac{30}{10}} - {\dfrac{3}{10}} $ $ = - \dfrac{{30} - {3}}{10} $ $ = -\dfrac{33}{10}$